Icelandic volcanoes slumber today, but not forever

Eruptions pepper the North Atlantic island

SELFOSS, Iceland — For a volcano that once paralyzed most of Europe, Eyjafjallajökull is surprisingly peaceful.

Everyone’s favorite unpronounceable Icelandic volcano grabbed headlines two years ago, when erupting magma hit a glacier and ash exploded into the sky. Nearly everyone has a story about where they were when aviation officials grounded European flights for days, because of the dangers of flying through volcanic ash.

After that eruptive burst, though, Eyjafjallajökull (pronounced AY-ya-fyat-la-yo-kult) dozed back off. Today it slumbers peacefully, a hulking ice-capped mountain that rises near Iceland’s south coast. (The volcano gets its name from where it sits: it’s a mountain (fjall) near the coastal island (eyja) with a glacier (jökull) on top.)

Anyone can marvel at Eyjafjallajökull from the nicely paved ring road that encircles Iceland. But getting up close and personal on the volcano’s northern side requires a bone-rattling trip on outwash plains, fording rivers time and again. Naturally, this is where geologists want to go. Especially geologists who were in Iceland on June 13 for an American Geophysical Union conference on volcanism and the atmosphere.

Here an outlet glacier creeps down like a frozen bluish tongue from the mountain’s summit. Before April 14, 2010, this massive river of ice flowed into a lagoon on the valley floor, with chunks of broken-off ice floating serenely in the water. The lake had, in fact, been growing as the glacier above it melted and retreated in warmer climes.

But then Eyjafjallajökull roared to life. Huge columns of ash thundered into the skies, mostly drifting to the mountain’s south and east. On this northern side, the eruption melted ice on the mountain’s summit, squirting a huge jet of meltwater into the once-peaceful lagoon. Within 20 minutes, the stream gauges set up in the valley to warn of such floods were washed away by the churning maelstrom, says Ármann Höskuldsson, a geologist at the University of Iceland in Reykjavik. Within hours the lagoon vanished, filled in by dirt and rocks.

Today the landscape underfoot tells a story of the volcano’s history. There’s the light-colored jumble of “hyaloclastite” that made up much of Eyjafjallajökull before it blew; black glassy fragments, studded with gemlike crystals of twinkling green olivine, from the 2010 eruption; and fine ash everywhere, blowing ceaselessly into eyes and camera cases. Here and there lie huge depressions that look like giant ant lion traps: kettle pits, the remains left behind where a huge chunk of ice once rested and then melted away.

To Icelanders, Eyjafjallajökull was a temporary nuisance that cut back on the island’s crucial tourist business. To the rest of the world, it was a permanent reminder of how dependent humans are on the whims of nature. Modern jet engines simply aren’t built to function in high levels of volcanic ash, and so when the winds carried Eyjafjallajökull’s ash eastward, much of Europe ground to a halt.

At the Iceland meeting, scientists floated some new ideas about how to better measure ash spreading from volcanoes like this one. David Pieri, of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., wants to send tiny drones, balloons or even miniature dirigibles over erupting volcanoes to get a better handle on how much ash is coming out. Fred Prata, of the Norwegian Institute for Air Research in Kjeller, is helping test a new sensor with the cunning acronym of AVOID (Airborne Volcanic Object Identifier and Detector), which would fly aboard passenger jets and alert pilots to levels of volcanic ash.

Yet Eyjafjallajökull isn’t even close to the worst Iceland can dish out. In 2011, the nearby volcano Grimsvötn spit out twice as much debris as Eyjafjallajökull in one-tenth the time, says John Stevenson of the University of Edinburgh. (It didn’t attract much attention outside of Iceland, however, since it didn’t close any European airspace.) And in 1783, the Laki volcano sent a toxic fog rolling across Iceland and all of Europe, killing 10,000 outright and changing the climate worldwide for years to come.

It’s a reminder of just how much volcanic power this little North Atlantic island has beneath it.